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Related papers: Seasonal variation of Saturn's Lyman-$\alpha$ brig…

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A planet's Lyman-{\alpha} (Ly{\alpha}) emission is sensitive to its thermospheric structure. Here, we report joint Hubble Space Telescope (HST) and Cassini cross-calibration observations of the Saturn Ly{\alpha} emission made two weeks…

Earth and Planetary Astrophysics · Physics 2023-11-27 Lotfi Ben-Jaffel , Julie Moses , Robert A. West , M-K. aye , Eric T. Bradley , John T. Clarke , Jay B. Holber , Gilda E. Ballester

Recent observations of interplanetary medium (IPM) atomic hydrogen Lyman-{\alpha} (Ly{\alpha}) emission in the outer solar system, made with the Alice ultraviolet spectrograph on New Horizons (NH), are presented. The observations include…

A multi-decade record of ground-based mid-infrared (7-25 $\mu$m) images of Saturn is used to explore seasonal and non-seasonal variability in thermal emission over more than a Saturnian year (1984-2022). Thermal emission measured by 3-m and…

We present observations and results of radiance and irradiance studies completed by SoHO-SUMER during the past solar cycle. We find that the cycle variation in Ly-alpha irradiance as observed by e.g. UARS-SOLSTICE can not be explained by…

Solar and Stellar Astrophysics · Physics 2010-02-19 W. Curdt , H. Tian

Saturn's axial tilt of 26.7{\deg} produces seasons in a similar way as on Earth. Both the stratospheric temperature and composition are affected by this latitudinally varying insolation along Saturn's orbital path. A new time dependent 2D…

Earth and Planetary Astrophysics · Physics 2015-06-03 Vincent Hue , Thibault Cavalié , Michel Dobrijevic , Franck Hersant , Thomas K. Greathouse

Cassini/ISS imagery and Cassini/VIMS spectral imaging observations from 0.35 to 5.12 microns show that between 2012 and 2017 the region poleward of the Saturn's northern hexagon changed from dark blue/green to a moderately brighter gold…

Earth and Planetary Astrophysics · Physics 2021-08-03 L. A. Sromovsky , K. H. Baines , P. M. Fry

In this work, we present for the first time the Lyman $\alpha$ intensities measured by Voyager 1/UVS in 2003-2014 (at 90-130 AU from the Sun). During this period Voyager 1 measured the Lyman $\alpha$ emission in the outer heliosphere at an…

Solar and Stellar Astrophysics · Physics 2017-10-20 O. A. Katushkina , E. Quemerais , V. V. Izmodenov , R. Lallement , B. R. Sandel

We analyze data from the final two years of the Cassini mission to retrieve the distributions of methane, ethane, acetylene, ethylene, and benzene in Saturn's upper stratosphere and mesosphere from stellar occultations observed by the…

Earth and Planetary Astrophysics · Physics 2024-05-06 Zarah L. Brown , Tommi T. Koskinen , Julianne I. Moses , Sandrine Guerlet

The longevity of Cassini's exploration of Saturn's atmosphere (a third of a Saturnian year) means that we have been able to track the seasonal evolution of atmospheric temperatures, chemistry and cloud opacity over almost every season, from…

Earth and Planetary Astrophysics · Physics 2015-10-21 Leigh N. Fletcher , Thomas K. Greathouse , Julianne I. Moses , Sandrine Guerlet , Robert A. West

Observations of the Sun's surface suggest a nonuniform radiated flux as related to the presence of bright active regions and darker coronal holes. The variations of the FUV/EUV source radiation can be expected to affect the Lyman-alpha…

Solar and Stellar Astrophysics · Physics 2021-10-04 Marek Strumik , Maciej Bzowski , Marzena A. Kubiak

Far-IR 16-1000 $\mu$m spectra of Saturn's hydrogen-helium continuum measured by Cassini's Composite Infrared Spectrometer (CIRS) are inverted to construct a near-continuous record of upper tropospheric (70-700 mbar) temperatures and…

Earth and Planetary Astrophysics · Physics 2015-10-14 Leigh N. Fletcher , Patrick G. J. Irwin , Richard K. Achterberg , Glenn S. Orton , F. Michael Flasar

This review summarizes our current understanding of the outer heliosphere and local interstellar medium (LISM) inferred from observations and modeling of interplanetary Lyman-$\alpha$ emission. The emission is produced by solar Lyman-alpha…

Solar and Stellar Astrophysics · Physics 2022-08-03 I. Baliukin , J. L. Bertaux , M. Bzowski , V. Izmodenov , R. Lallement , E. Provornikova , E. Quemerais

We present an analysis of HI Lyman-alpha emission in deep VLT/MUSE observations of two highly magnified and extended galaxies at z=3.5 and 4.03, including a newly discovered, almost complete Einstein ring. While these Lyman-alpha haloes are…

The incredible longevity of Cassini's orbital mission at Saturn has provided the most comprehensive exploration of a seasonal giant planet to date. This review explores Saturn's changing global temperatures, composition, and aerosol…

Earth and Planetary Astrophysics · Physics 2023-05-09 L. N. Fletcher , L. Sromovsky , V. Hue , J. I. Moses , S. Guerlet , R. A. West , T. Koskinen

Saturn's northern summertime hemisphere was mapped by JWST/MIRI (4.9-27.9 $\mu$m) in November 2022, tracing the seasonal evolution of temperatures, aerosols, and chemical species in the five years since the end of the Cassini mission. The…

The seasonal evolution of Saturn's polar atmospheric temperatures and hydrocarbon composition is derived from a decade of Cassini Composite Infrared Spectrometer (CIRS) 7-16 $\mu$m thermal infrared spectroscopy. We construct a…

We used 0.85 - 5.1 micron 2006 observations by Cassini's Visual and Infrared Mapping Spectrometer (VIMS) to constrain the unusual vertical structure and compositions of cloud layers in Saturn's south polar region, the site of a powerful…

Earth and Planetary Astrophysics · Physics 2019-08-23 Lawrence A. Sromovsky , Kevin H. Baines , Patrick M. Fry

Recent studies of interstellar neutral (ISN) hydrogen observed by the Interstellar Boundary Explorer (IBEX) suggested that the present understanding of the radiation pressure acting on hydrogen atoms in the heliosphere should be revised.…

Solar and Stellar Astrophysics · Physics 2018-02-05 Izabela Kowalska-Leszczynska , Maciej Bzowski , Justyna M. Sokół , Marzena A. Kubiak

An image of Lyman-$\alpha$ (Ly$\alpha$) emission from Europa obtained with the Hubble Space Telescope Space Telescope Imaging Spectrograph (HST/STIS) has previously provided the first evidence of localized water vapor (H$_2$O) aurora,…

We present a study of the influence of solar UV anisotropy on the heliospheric backscatter helioglow generated by resonant scattering of solar Lyman-alpha photons on interstellar hydrogen atoms around the Sun. Simulations based on the…

Solar and Stellar Astrophysics · Physics 2023-12-22 M. Strumik , M. Bzowski , M. A. Kubiak
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